The present invention relates generally to tamper proof seals for containers such as bottles and the like and, specifically, to an inner seal having a pull tab formed thereon by affixing an outer laminate to a portion of the top of the seal.
In the packaging of certain products, such as bottled products, it is desirable to provide a seal that retains the freshness of the products and that indicates tampering of the seal. Moreover, it is desirable that such seal be easily removable by the end user of the product.
U.S. Pat. No. 4,501,371 discloses a tamper indicating, non-resealable closure or seal for a container. The closure includes a foil sheet having a layer of thermoplastic material on each surface thereof. The foil sheet is thermally bonded to a container opening. A liner ring overlies the foil sheet and is thermally bonded to the thermoplastic material of the foil.
More recently, another seal is disclosed in an advertisement placed by Stanpac, Inc., a Canadian corporation located in Smithville, Ontario. The Stanpac advertisement, appearing at page 70 of the March, 1988 issue of Packaging Digest, discloses a peel-off tamper indicating seal for a container having multiple layers and a tab formed thereon. The seal includes a layer of 0.0015 inches thick aluminum foil with a coating of heat activated adhesive on its bottom surface. Half of a 0.005 inches two-ply sheet formed of polyester laminated two paper is glued to the top surface of the aluminum foil. The seal is shaped like a disc with the unattached half of the polyester-laminated-to-paper sheet forming a pull-tab used to peel off the seal from a container.
The disclosed stampac stamped seal, however, has several drawbacks. The paper layer employed in the tab is susceptible to curling in the presence of moisture. Additionally, because the tab flaps freely, it can become misaligned during capping of a container and then can get in the way of the cap.